Reversible rotary impact tool



May 29, 1956 A c BURLEIGH 2,747,447

REVERSIBLE ROTARY IMPACT TOOL Filed Nov. 1, 1954 2 Sheets-Sheet l FIG. I;

IN V EN TOR.

(Ari/wt 6T afiurlezlyk. BY Lug. 0.4m;

May 29, 1956 2,747,447

REVERSIBLE ROTARY IMPACT TOOL Filed NOV. 1, 1954 2 Sheets-Sheet 2 IN VEN TOR.

Jrihur 6'. fiurieiylz.

BY 2 E Z United States Patent Office 2,747,447 Patented May 29, .1956

REVERSIBLE ROTARY IMPACT TOOL Arthur C. Burleigh, Wellesley, Mass.

Application November 1, 1954, Serial No. 466,053

8 Claims. (Cl. 81-52.3)

This invention relates to a rotary impact tool such as is commonly used for driving screws or screwing nuts onto bolts or studs, the impact feature of the tool coming into play for tightening the screw or nut when it has been driven home.

One of the objects of the present invention is to provide a novel reversible driving mechanism for the driven shaft to which the screw driver, nut socket, or similar tool is attached and which will be hereinafter referred to as the tool-carrying shaft.

A further object of the invention is to provide a tool of this type which can be used as an adjunct to a nonimpact-producing power tool, such as an electric drill, for the purpose of converting said power tool into one capable of producing a succession of impacts or rotational hammer like blows for the purpose of tightening a screw or a nut.

In the drawings wherein I have illustrated a selected embodiment of the invention,

Fig. 1 is a sectional view of an impact tool having my improved reversing mechanism and showing the said mechanism set for driving the tool-carrying shaft in the same direction as the drive shaft;

Fig. 2 is a similar sectional view showing the reversing mechanism set for driving the tool-carrying shaft in a direction opposite to that of the driving shaft;

Fig. 3 is a detail of the reversing mechanism;

Fig. 4 is a section on the line 44, Fig. 2;

Fig. 5 is a section on the line 55, Fig. 1;

Fig. 6 is a view showing the under side of the head of the tool-carrying shaft.

In the drawings, 1 indicates a driving shaft which may be operated from any suitable source of power, and 2 indicates a tool-carrying shaft which is adapted to carry at its lower end 3 any desired tool such as a screw driver, if the device is to be used for driving screws, or a Wrench socket if the device is to be used for turning nuts on a bolt.

These two shafts are mounted in a suitable casing 4, said shafts being arranged in axial alinement with the driving shaft 1 extending through a suitable bearing 5 in the upper end of the casing, and the tool-carrying shaft 2 having a bearing in the lower end 6 of the casing, said lower end being removable from the casing but detachably secured thereto by screws 7.

Located within the casing is a rotatable power transmitting member indicated generally at 8, by which the rotary motion of the driving shaft 1 is transmitted to the tool-carrying shaft 2, said member having a bearing 9 for the lower end 10 of the driving shaft 1.

The power-transmitting member 8 is operatively connected to the driving shaft 1 through a reversible driving mechanism, which will be presently described, and by which the said power transmitting member may be driven in either direction relative to the driving shaft 1.

Thepower-transmitting member 8 by which the rotary motion of the driving shaft 1 is transmitted to the toolcarryin'g shaft 2 is herein shown as presenting an upper section 11 and a lower section 12 which are rigidly secured together, the lower section 12 having an axial through opening in which the tool-carrying shaft 2 is received. Said shaft 2 is formed at its upper end with a head 19 which is received in a chamber 54-with which the powertransmitting member 8 is provided, and an annular friction pad 55 is provided for transmitting rotational movement of the power-transmitting member 8 to the head 19 and thus to the tool-carrying shaft 2. This friction pad 5:5 has frictional engagement with the top face of the head 19, and also frictional engagement with the top face 56 of the chamber 54. The head 19 is yieldingly pressed against the friction pad 55 by means of springs 20 which are locatedin openings 13 formed in the lower section 12 of the power-transmitting member. Each spring 20 bears at its upper end against an upper ball 16 which is partially received in the upper end of the corresponding opening and is partially received in a curved groove 18 formed in the under face of the head 19. The lower end of each spring 26 bears against a lower ball 14 which is partially received in the lower end of the cor-responding opening. 13 and which seats in an annular groove 15 formed in a plate 169 which is screw-threaded to the projecting hub portion 17 of the lower section 12.

The frictional engagement of the friction pad 55 with the head 19 and the face 56 of the section 12 resulting from the pressure of the springs 29 is sufiicient to transmit the rotative movement of the power-transmitting member 3 to the head 19 and thus to the shaft 2 during the operation of driving a screw or running a nut on a bolt or stud. When, however, the torque resistance. of the tool-carrying shaft 2 increases beyond a predetermined point as the screw or nut is being driven home, the powertransmitting member 8 will rotate forwardly relative to the shaft 2, thus bringing the balls 16 up against the ends of the grooves 18, and if the shaft is rotating rapidly this will result in giving the shaft an impact or rotational hammer-like blow. As the power-transmitting member continues to rotate forwardly relative to the shaft, the upper balls 16 are forced downwardly into the openings 13 against the action of the springs 29 and said powertransrnitting member will rotate freely until the balls drop into the next groove 18, and as the balls travel in said grooves 18 they will be brought up against the ends of the groove with a sharp impact which will give the toolcarrying shaft a second rotational hammer-like blow. These impacts will succeed each other in rapid fashion and thereby the screw or nut will be properly tightened.

Means are provide whereby the normal spring pressure of the springs 20 against the balls 16 may be varied, thereby to vary the strength of the impact blows. It has been stated that the member 166 is screw-threaded to the hub portion 17 of the lower section 12. By screwing said member 16% upwardly on the hub, the tension of the springs will be increased, thereby providing for delivering impact blows of increased intensity; while if the member 16% is screwed downwardly, the tension of the springs 29 will be relieved somewhat, with the result that the impact blows will be of reduced intensity.

For thus adjusting the member the latter is provided with recesses 161 in its periphery and the lower member 12 is provided with a recess 162. The casing 4 is also provided with an opening 163 through which the recesses 161 and 162 are accessible.

By inserting a pin in the recess 162 and another pin in the recess 161, the power-transmitting member 8 can be held stationary while the member 160 is turned in one direction or another either to increase the tension of the springs 20 or to reduce their tension. It will be understood that the member 160 will have a plurality of recesses 161 in its periphery which can be successively used for turning the said member.

The 'reversible driving drive shaft and which is driven thereby in a direction opposite to that in which the driving shaft rotates.

it is desired to rotate the tool-carrying shaft 2.

For rotating the upper driving member 23 there is provided a bevel gear 24 which is fast on the driving shaft 1 and which meshes with two or more intermediate bevel gears 25 each of which is rotatively mounted on a short shaft 26 supported at its outer end in a bearing member 27 rigidly secured within the housing 4, each shaft 26 being supported at its inner end in a collar 28 encircling the driving shaft 1. The upper bearing member 23 is provided with bevel gear teeth 29 with which the intermediate gears 25 mesh, and thereby the upper bearing member is rotated about the shaft 1, but in an opposite direction from that in which said shaft rotates. The power transmitting member 8 is operatively connected to either the upper driving member 23 or the lower driving member 21 through a reversing member 30 in the form of a ring which encircles the portion 31 of the upper hearing member and is mounted for vertical movement.

This reversing member 30 has on its under side a series of radial teeth 32 which are adapted to mesh with complementary teeth or ribs 33 carried by the upper side of the lower bearing member 21, and said reversing member carries on its upper side radial teeth or ribs 34 adapted to engage complementary teeth 35 formed on the under side of the driving member 23. The reversing member 30 is connected to the power transmitting member 8 through the medium of pins 36 which are anchored in the power transmitting member and which extend through openings in the reversing member 30.

Means are provided for moving the reversing member in a vertical direction, thereby to bring the radial teeth 32 V.

and 33 into mesh when the tool-carrying shaft is to be rotated in the same direction as the driving shaft, or to bring the teeth 34, 35 into mesh when said tool-carrying shaft is to be rotated in a direction opposite to that of the driving shaft.

The reversing member 30 is mounted for rotation in a ring element 38 which is located inside of the housing, said element 38 having an interior groove 39 in which the outer edge of the reversing member 30 is received. The interior ring 38 is secured by bolts 49 to an exterior operating ring 41 which is located on the exterior of the casing 4, said bolts passing through slots 42 with which the casing 4 is provided. The slots 42 are in the nature of cam slots, each slot having a low portion 43 and a high portion 44 connected by an inclined portion 45. The operating ring 41 and the interior ring 38 are capable of turning movement relative to the casing, and during such turning movement the bolts 40 move from one end to the other of the slots 42. When the rings 41 and 38 are adjustedtso that the bolts 4% are in the low portions 43 of the slots 42, the reversing member 30 will be in its low position and in operative engagement with the lower driving member 21. When, however, the rings 41 and 38 are turned to move the bolts 40 to the upper portions 44 of the slots 42, both rings will be moved upwardly during their turning movement and the reversing member 30 will be moved upwardly into operative engagement with the upper driving member, as shown in Fig. 2.

Hence, when the tool-carrying shaft 2 is to be rotated in the same direction as the driving shaft, the rings 41 and 38 will be turned to carry the bolts 40 into the low portions of the slots 42, as shown in Fig. 1, while when t 4 a a the shaft 2 is to be rotated in a direction opposite to that of the driving shaft 1 said rings will be turned to move the bolts 40 into the upper portions of the slots, as shown in Fig. 2.

By adjusting the rings 41 and 38 into an intermediate position the reversing member 30 may be disconnected from both driving members so that the driving shaft may rotate freely without giving rotation to the tool-carrying shaft 2. a

Another feature of the invention relates to a construction whereby the tool above described can be used as an adjunct to atnon-impact-producing power tool such as an electric drill for the purpose of converting such power tool into an impact-producing tool. For this purpose the driving shaft 1 is provided with a free end which extends beyond the casing 4 and which is adapted to be connected to the driven shaft of a power tool such as an electric drill. This will easily be done by mounting the free end 70 in the chuck of the electric drill and then applying to the end 3 of the tool-carrying shaft 2 the screw driver, wrench socket or other appropriate tool. When thus connected to the power tool the latter provides the driving power for rotating the shaft 1, and the tool illustrated in Fig. 1 provides the impact-producing feature by which the power tool is converted into an impact producing tool. 7

When used in this way it is necessary that the casing 4 should be held from rotation during the operation of the device, and for this purpose the casing 4 has rigid therewith a handle 71 which may be grasped by an operator and by which said casing is prevented from rotative movement.

I claim: 7

l. A reversible rotary impact tool comprising a rotatable driving shaft, a tool-carrying shaft coaxial therewith, a rotatable power-transmitting member also coaxial with said driving shaft, impact producing means operatively connecting the power-transmitting member to the toolcarrying shaft, and a reversible driving connection for transmitting rotary motion from'the driving shaft to the power-transmitting member, said reversible driving connection comprising a first driving member rigid with the driving shaft, a second driving member mounted for rotation about the driving shaft, means operated by the driving shaft for rotating the second driving member in a direction opposite to that in which the driving shaft is rotated, and meansfor operatively connecting the powertransmittin g member to either driving member.

2. A reversible rotary impact tool as defined in claim 1 in which the driving members are spaced from each other in the axial direction of the driving shaft and which includes a reversing member situated between the dr iving members and rotatable about theaxis thereof, means to move the reversing member into operative driving engagement with either driving member, and means connecting the reversing member to the power-transmitting member.

3. A reversible rotary impact tool comprising a rotatable driving shaft, a tool-carrying shaft, a rotatable powertransmitting member, impact producing means operatively connecting the power-transmitting member to the tool-carrying shaft, a reversible drivingconnection for transferring rotary motion from the driving shaft to the power-transmitting member, said reversible driving connection comprising a first driving member rigid withthe driving shaft, a tool-carrying shaft, a rotatable power-transmitting member, impact producing means operatively connecting the power-transmitting member to the toolcarrying shaft, and a reversible driving connection for transmitting rotary motion from the driving shaft to the power-transmitting member, said reversible driving connection comprising a first driving member rigid with the driving shaft, a second driving member mounted for rotation about the driving shaft, means for rotating the second driving member in a direction opposite to that in which the driving shaft is rotated, a casing enclosing the powertransmitting member, impact producing member and reversing driving connections, and means operable from the exterior of the casing for operatively connecting the power-transmitting member to either driving member.

5, A reversible rotary impact tool comprising a rotatable driving shaft, a tool-carrying shaft, a rotatable power-transmitting member, impact producing means operatively connecting the power-transmitting member to the tool-carrying shaft, and a reversible driving connection for transmitting rotary motion from the driving shaft to the power-transmitting member, said reversible driving connection comprising a first driving member rigid with the driving shaft, a second driving member mounted for rotation about the driving shaft, means for rotating the second driving member in a direction opposite to that in which the driving shaft is rotated, a casing enclosing the power-transmitting member, the impact producing member and the reversing driving connections, a control ring surrounding the casing movable thereon relative thereto, and means actuated by the control ring to operatively connect the power-transmitting member to either driving member.

6. A reversible tool comprising a rotatable driving shaft, a tool-carrying shaft, a rotatable power-transmitting member operatively connected to the tool-carrying shaft, a reversible driving connection for transferring the rotary motion from the driving shaft to the power-transmitting member, said reversible driving connection comprising a first driving member rigid with the driving shaft, a second driving member coaxial with the first driving member and mounted for rotative movement about the driving shaft, said driving members being spaced from each other in the direction of the axis of the driving shaft, means connecting the second driving member to the driving shaft and operative to rotate said second driving member in a direction opposite to that in which the driving shaft is rotated and means for operatively connecting the powertransmitting member to either driving member.

7. A device of the class comprising a rotatable driving shaft, a tool-carrying shaft, a rotatable power-transmitting member operatively connected to the tool-carrying shaft, and a reversing driving conection for transmitting rotary motion from the driving shaft to the power-transmitting member, said reversing mechanism comprising a first driving member rigid with the driving shaft, a second driving member coaxial with the first driving member but spaced therefrom in the direction of the axis of the driving shaft, means rotating the second driving member in a direction opposite to that in which the driving saft is rotated, a reversing member situated between the driving members and rotatable about the axes thereof, means connecting the reversing member to the power-transmitting member, and means for moving the reversing member into operative driving engagement with either driving member.

8. A device of the class described comprising a rotatable driving shaft, a tool-carrying shaft, a rotatable powertransmitting member operatively connected to the toolcarrying shaft, and a reversing driving connection for transmitting rotary motion from the driving shaft to the power-transmitting member, said reversing mechanism comprising a first driving member rigid with the driving shaft, a second driving member coaxial with the first driving member but spaced therefrom in the direction of the axis of the driving shaft, means rotating the second driving member in a direction opposite to that in which the driving shaft is rotated, a reversing member situated between the driving members and rotatable about the axes thereof, means connecting the reversing member to the power-transmitting member, a casing enclosing the powertransmitting member and the driving members, and means operable from the exterior of the casing for moving the reversing member into operative engagement with either driving member.

References Cited in the file of this patent UNITED STATES PATENTS 2,049,273 Pott July 28, 1936 2,246,648 Van Sittert et al June 24, 1941 2,285,639 Amtsberg June 9, 1942 2,326,347 Forss Aug, 10, 1943 2,341,497 Amtsberg Feb. 8, 1944 2,366,859 Koza Ian. 9, 1945 2,576,851 Newman Nov. 27, 1951 2,591,323 Webb Apr. 1, 1952 

